The invention generally relates to video and graphics pipelines and more particularly to high quality video and graphics pipelines.
Combined processing pipelines for video/graphics are used in processing and/or display pipelines for video/graphics manipulation and composition. A typical combined video/graphics pipeline includes components for pixel formatting, color lookup tables, color space conversion, transformation filtering for 4:2:2 to 4:4:4 and 4:4:4 to 4:2:2 conversions, pixel mixing and alpha blending. Usually, in such pipeline video/graphics data transformations are performed in multiple chips at multiple places from one color space to another. These transformations cause considerable picture damage. The resulting quality of the processing is noticeable on the display devices for traditional consumer products to which incapable of displaying high resolution, high quality video/graphics is not essential. The recent HDTV (high definition television) market and the trend of converging TV and PC applications now demand higher quality video/graphics processing in consumer products. Images with noticeable artifacts due to improper processing are no longer acceptable.
Therefore, there is a need for an optimal pipeline suitable for high quality video/graphics processing.
The present invention provides an optimal processing pipeline suitable for high quality video and graphics processing. According to the invention, color key extraction is performed before actual processing and transforming of the video/graphics data. This substantially minimizes the amount of artifacts in composed pictures.
In accordance with the present invention, an video/graphics data processing pipeline is provided. The pipeline comprises a pre-processing circuit that is configured to pre-process a stream of digital video/graphics data and output pre-processed data; a color key processing circuit, operably coupled to the pre-processing circuit, that is configured to extract a color key from the pre-processed data and output resulting data; and a processing/transforming circuit, operably coupled to the color key processing circuit, that is configured to process and transform the resulting data.
According to one aspect of the invention, the color key processing circuit includes a color substitution circuit that is configured to substitute the color key with a pre-selected color.
According to another aspect of the invention, the processing/transforming circuit includes a up-filtering circuit, operably coupled to the color key processing circuit, that is configured to perform up-filtering on the resulting data and output up-filtered data; and a conversion circuit, operably coupled to the up-filtering circuit, that is configured to perform color space conversion on the up-filtered data and output converted data. The processing/transforming circuit further includes a down-filtering circuit, operably coupled to the conversion circuit, that is configured to perform down-filtering on converted data. The up-filtering and down-filtering performed by the up-filtering and down-filtering circuits respectively are mutually exclusive.
According to yet another aspect of the invention, the pre-processing circuit includes a data formatting circuit that is configured to perform pixel formatting, color expansion and alpha extraction on the video/graphics data and output formatted data; and a color look-up table (CLUT) circuit, operably coupled to the formatting circuit, that is configured to perform indexing on the formatted data.